Dielectric, elastic and piezoelectric losses of PZT ceramics in the resonance state

The material coefficients of "soft"- and "hard"-PZTs were determined as complex values by the non-linear least-squares-fitting of immittance data measured for length-extensional bar resonators. The piezoelectric d-constant should be a complex value to obtain a best fitting between observed and calculated results. As the elastic, dielectric and piezoelectric losses determined in this process were not "intrinsic" losses, calculation process to evaluate the "intrinsic" losses was proposed. It was confirmed that the intrinsic losses were smaller than the corresponding extrinsic losses. The intrinsic piezoelectric loss existed in both soft- and hard-PZTs. About 50% of the loss of piezoelectric d-constant was derived from the elastic and dielectric losses. Most notable difference between the soft- and hard-PZTs were observed in their elastic losses.